1. Field of the Invention
This invention relates to a light weight portable dispenser containing a chemical generator which provides medically pure oxygen at a controlled delivery rate for direct human inhalation. Specifically, this invention utilizes the creation of oxygen from completely inert compounds with extended shelf life in a contained chemical reaction which can be instantly activated in this totally safe and reliable personal dispenser.
2. Description of Related Art
In order to completely understand and appreciate this invention in its unique context, reference will be made to a number of prior art patents and publications contained therein, in the following text.
Chemical oxygen generators, formed of an alkali metal chlorate and one or more sodium or potassium oxides, cited as related art in U.S. Pat. No. 3,702,305 (Thompson) have been known for some time. Those cited in the above Patent include: U.S. Pat. Nos. 2,469,414; 2,558,756; 2,775,511; 3,207,695; 3,276,846 and 3,233,187. All require a separate substance such as iron, charcoal, magnesium or manganese to maintain combustion, which is the "oxygen creating" reaction, with its attendant high heat evolution and the creation of impurities. Thompson, in his above referenced Patent, and in his subsequent U.S. Patents: U.S. Pat. Nos. 3,725,156; 3,736,104; 3,749,678; 3,806,323 and 3,861,880 has provided the art with examples of fuel-less, water-initiable, low-heat evolution, catalytic decomposition chemical oxygen generators that lend themselves far more favorably to personal, safe portability. U.S. Pat. No. 3,733,008 (Churchill, Thompson & McBride) introduced lightweight compact and convenient carrying cases, or dispensers, containing a plurality of oxygen generators with a carrying strap and detached mask or cannula. This Patent included in its claims, "replaceably receiving at least one oxygen generating canister," which would work without losing oxygen because of the ball-seated check valves included in each of the three orifice ports. However, their applications did not address a "single generator" carrying case or dispenser.
In U.S. Pat. No. 3,736,104 (Churchill & Thompson), while introducing to the art various embodiments of thin-walled tin plated steel cans, electrically and chemically initiated generators, differences in starting cone compounds, and a number of physical generator characteristics, did illustrate in FIG. 9, & FIG. 10, methods of activating a single generator with outlet delivery tubes identified. These were not, however, carried to practicable completion as single generator `personal` dispensers because the temperature of the oxygen at the outlet tube is between 400.degree. F. and 460.degree. F., far too hot for direct human inhalation. (See U.S. Pat. Nos. 2,121,347 & 3,725,156). In a similar addition to related art, U.S. Pat. No. 3,986,838 (Reicherr) the subject matter focused primarily on the fracturability and mounting options of glass vial, capsule or ampoule ignition techniques. This Patent referred to the same FIG. 10 cited above in U.S. Pat. No. 3,736,104 (Thompson) as a method to activate a single generator in its own dispenser; the disclosure was, however, not carried to practicable completion either, and also delivered oxygen far too hot for direct human inhalation.
Prior to the above improvements, the related art included the disclosures of U.S. Pat. Nos. 2,121,347 (Hausmann) and 2,558,756 (Jackson) which described single cell generators, however, as cumbersome and not appropriate for carrying as a personal accessory. In addition, the prior art included U.S. Pat. Nos. 2,507,450 (Millikan et al), 3,276,846 (Montet al) and 3,580,250 (Oroza) which disclosed the requirements for elaborate starting mechanisms and expensive heavy insulated containers in order to handle the hazardous high temperature combustion. These were considered too expensive to market as off-the-shelf items and did not provide medically pure oxygen.
A more recent addition to the related art is included in U.S. Pat. No. 3,955,931 (Thompson) which introduces a single generator with a snap-on cap acting as a dispenser, and an enclosed mask which, however, employs a relatively complex packaging and insulation technique. This consists of a generator jacket, or shroud, of hydrate salts sandwiched between layers of metal foil-backed refractory fibers, and which may require a moisture proof shelf-life storage envelope. A concern inherent to the hydrate salt refractory fiber jacket, which makes possible the ability to "handle" the generator itself with bare hands, during or immediately following the reaction cycle, appears to be the negative effect of reducing the personal portability of the unit. Another concern within the technology of this patent occurs when the snap-on cap is removed to facilitate replacement activity, thus exposing the bare area of the top of the used generator to the operator or patient, which has a stated temperature of 627.degree. F. according to Example III of this patent. A further concern noted in Example III of this patent is the apparent temperature of the oxygen at the exit orifice of the generator, which is near or at the stated 627.degree. F. of the generator (canister) surface temperature, and the consequent improbability that a delivery robing of normal length will cool this oxygen to near body temperature prior to reaching the mask for inhalation.
A mote serious concern, however, emerges when considering the consequences of a rupture in the moisture proof envelope during the shelf-life storage permitting the hydrate salts to effloresce, or any hydrate salt to decompose in any manner with or without a protective envelope. At that point the means of converting the sensible heat of the exothermic reaction cycle to the heat of evaporation has been eliminated, and in fact, replaced with external insulation on the generator, which according to Example II in this patent, appears to drive the generator wall temperature toward 3000.degree. F.
While the above cited references introduce and disclose a number of noteworthy advances and technological improvements within the art, none completely fulfills the specific objectives achieved by this invention.